In vivo imaging method visualizes bone-resorbing cell function in real time

Aug. 17, 2016
In vivo imaging can visualize sites where osteoclasts (bone-resorbing cells) were in the process of resorbing bone.

Researchers at at the Immunology Frontier Research Center (IFReC) at Osaka University (Japan) have discovered a way to visualize sites where osteoclasts (bone-resorbing cells) were in the process of resorbing bone in vivo. This real-time visualization of changes in osteoclast localization and activity allowed measurement of bone resorption intensity, and the work could someday contribute to early diagnosis of affected areas and the development of new therapeutic drugs.

Osteoclasts are bone-resorbing cells that may cause osteoporosis and rheumatoid arthritis if there is an excess in bone resorption. So far, information on osteoclast localization could be gathered by using fluorescent proteins, but this method did not allow an examination of osteoclast activity. So the researchers, led by Kazuya Kikuchi, professor at the Graduate School of Engineering, and Masaru Ishii, professor at the Graduate School of Medicine, produced fluorescent probes that visualize those sites where osteoclasts are in the process of resorbing bone and developed their own imaging device. They thereby conducted an in vivo evaluation of osteoclast function.

In vivo excitation spectra of pHocas-3 and tdTomato.

The research team developed a mechanism by which small molecular probes (SMPs) are selectively delivered to the location of target cells. Up until then, application of SMPs to in vivo imaging was particularly challenging, as delivery to target tissues proved difficult. The researchers managed to optimize molecular delivery so that the molecular probes only had to be injected into the mice for imaging. The SMPs were equipped with a switch function that is only triggered at those areas where bone is being resorbed. This enabled the selective visualization of osteoclast activity. In combination with fluorescent proteins that label target cells, the researchers succeeded in real-time visualization of changes in cell localization and activity as well as the measurement of bone resorption intensity.

Photostable pH-activatable probe.

This research will have great impact in the field of in vivo imaging, as it established a method that allows simple and quick measurement in detecting osteoclasts that are in the process of resorbing bone. This could also benefit early diagnosis and the screening of new therapeutic drugs. The findings also could be applied to molecular design based on physical chemistry principles, creation of functional fluorescent probes by synthetic organic chemistry, and clarification of intravital mechanisms using immunological knowledge and technology.

Full details of the work appear in the journal Nature Chemical Biology; for more information, please visit http://dx.doi.org/10.1038/nchembio.2096.

About the Author

BioOptics World Editors

We edited the content of this article, which was contributed by outside sources, to fit our style and substance requirements. (Editor’s Note: BioOptics World has folded as a brand and is now part of Laser Focus World, effective in 2022.)

Sponsored Recommendations

Demonstrating Flexible, Powerful 5-axis Laser Micromachining

Sept. 18, 2024
Five-axis scan heads offer fast and flexible solutions for generating precise holes, contoured slots and other geometries with fully defined cross sections. With a suitable system...

Enhance Your Experiments with Chroma's Spectra Viewer

Sept. 5, 2024
Visualize and compare fluorescence spectra with our interactive Spectra Viewer tool. Easily compare and optimize filters and fluorochromes for your experiments with this intuitive...

Optical Filter Orientation Guide

Sept. 5, 2024
Ensure optimal performance of your optical filters with our Orientation Guide. Learn the correct placement and handling techniques to maximize light transmission and filter efficiency...

Ensure Optimal Performance with Shortpass Filters

Sept. 5, 2024
Achieve precise wavelength blocking with our Shortpass Filters. Ideal for applications requiring effective light transmission and cutoff, these filters ensure optimal performance...

Voice your opinion!

To join the conversation, and become an exclusive member of Laser Focus World, create an account today!